1. FIELD OF THE INVENTION
This invention relates to an EL (Electroluminescence) element emitting light by application of an AC electric field and in particular to a multicolor EL element capable of emitting 3-colored light, red, green and blue. This invention relates further to a light emission method using such an EL element.
2. DESCRIPTION OF THE PRIOR ART
A thin film EL element, in which there are disposed a plurality of filters, which cut-off or transmit only light having a specified wavelength region in the direction parallel to the light emitting surface of a layer emitting light having a relatively large emission spectrum width so as to give rise to light emission having a plurality of colors, is disclosed in JP-A-57-25692. Concretely speeking, it is disclosed there that ZnS, to which PrF.sub.3 is added as activation material, is used as the light emitting layer, and red, bluish green and white colors are taken-out therefrom by means of a filter transmitting red light emission and another transmitting bluish green light emission.
However, by means of an element using only one kind of light emitting layers as by the prior art techniques described above, it is extremely difficult to obtain all the three primary colors, i.e., red, blue and green with a satisfactory brightness.